Moors & Christians / Moros y Cristianos Festivals (any experts on here?)

I'm sure like most on here I've been to these and generally if we pick the right night it's always been a spectacular occassion (always been Orihuela for me). I've read up on it a fair bit and although I have a basic understanding of the history behind it, I can never seem to fathom what the actual "action" will be on any particular night!

There's a good summary of this years Orihuela week (July 12th to 18th) via link below but aside from the "guns" bit I'm still confused as to what actually happens each night. From memory, the best nights I recall are simply those parades that never seem to stop, 2 or 3 hours marching with me sat on the side of the road directly outside a bar (little wonder I can't remember much!) 
http://www.eurotourguide.com/en/costa-blanca-south/events-calendar/orihuela-moors-christians-fiesta

So can anyone spill the beans or unfold the story for us? (I stress I'm purely referring to the celebrations now as opposed to the actual history behind it).

Thanks in anticipation.